This invention relates, in general, to semiconductors, and more particularly to processing of semiconductors wafers.
Corrosion or microcorrosion of metal films or metal surfaces that are used in manufacturing semiconductors has been a problem for a long time. Corrosion, which is an unintentional removal of metal from a metal film or from a metal surface, results in holes, depressions, voids, or openings being formed in the metal film or the metal surface. These holes, voids, depressions, or openings further result in electrical problems, such as noncontact, degraded or marginal contact, and decreased reliability, thereby producing marginal semiconductor devices.
Corrosion of metal surfaces or metal films that are made of aluminum alloys that have been doped with a copper impurity are especially susceptible to corrosion. The addition of the copper impurity to a predominantly aluminum film while having some benefits, such as hillock reduction and electromigration reduction, causes severe corrosion problems. Additionally, continual shrinking of geometric features have further exacerbated the corrosion problems of these films.
Therefore, a method to reduce corrosion in a simple, inexpensive, and an easily implemented procedure or method would be highly desirable.